The cost efficiency of dairy farms was analyzed for two leading production areas in Poland, i.e., Wielkopolskie and Podlaskie Voivodships. The analysis suggests that dairy farms in Podlaskie Vovivodship appear to have a closer gap in cost inefficiency as compared to the most efficient farm than corresponding farms in Wielkopolskie Voivodship. Wielkopolskie voivodship has a relatively larger number of farms that could substantially improve their cost efficiency Than Podlaskie Voivodship. However, the cost efficiency index value calculation method permits only an indirect comparison across regions, while the FADN data does not account for likely labor cost differences between the regions.